docs: def _handleSmsReceived(self, notificationLine):
          """ Handler for "new SMS" unsolicited notification line """
          self.log.debug('SMS message received')
          cmtiMatch = self.CMTI_REGEX.match(notificationLine)
          if cmtiMatch:
              msgMemory = cmtiMatch.group(1)
              msgIndex = cmtiMatch.group(2)
              sms = self.readStoredSms(msgIndex, msgMemory)
              self.deleteStoredSms(msgIndex)
              self.smsReceivedCallback(sms)